Giúp mình bài toán hình

V

vip112233

ta co: KD=DH=6(do tg AKD=tg AHD)
goi a=BH,b=DC
tg ABH ~ CDK
\RightarrowHB/KD=AB/CD\Rightarrowa/6=AB/b\Rightarrowab=6AB (1)
mat khac tg KCD~tg ACB
\Rightarrow6/AB=b/25\RightarrowAB/6=25/b\Rightarrow6AB=900/b(2)
tu(1) va(2)\Rightarrow a*b=900/b. Ma a=25-6-b=19-b.
\Leftrightarrow(19-b)b=900/b \Rightarrow19b^2 -b^3=900. tu do giai duoc b=-6(loai)- va b=15(tm) b=10(tm)
\Rightarrow tg KCD~ tg ACD theo k=o,6.va k*=0,4
\RightarrowAB=10cm. AB=15

con duong xaxaxax************************************aaaa
 
Last edited by a moderator:
You must log in or register to reply here.
Top Bottom